1. Field of the Invention:
This invention relates to compositions containing low-foam surfactants in which alkyl and/or alkenyl diethanolamine compounds are present as solubilizers.
2. Statement of Related Art:
U.S. Pat. No. 4,548,729 relates to the use of selected polyethylene glycol ethers corresponding to the following formula EQU R.sup.1 --O--(CH.sub.2 CH.sub.2 O).sub.n --R.sup.2 (I)
in which
R.sup.1 is a linear or branched chain C.sub.8 -C.sub.18 alkyl or alkenyl radical, PA1 R.sup.2 is a C.sub.4 -C.sub.8 alkyl radical, and PA1 n is a number of from 7 to 12, PA1 R.sub.1 is a linear or branched C.sub.8 -C.sub.18 alkyl or alkenyl radical, PA1 R.sub.2 is a C.sub.4 -C.sub.8 alkyl radical and PA1 n is a number of from 3 to 7, PA1 x is a number of from 1 to 3 and PA1 y is a number of from 3 to 6, and PA1 z is a number of from 1 to 3. PA1 r, s, t, u, v and w are integers of from 1 to 3, PA1 R.sub.5 is a linear or branched C.sub.8 -C.sub.18 alkyl or alkenyl radical, PA1 R.sub.6 is a C.sub.4 -C.sub.8 alkyl radical, and PA1 p is a number of from 3 to 7, PA1 x is a number of from 1 to 3, and PA1 y is a number of from 3 to 6, PA1 z is a number of from 1 to 3.
as foam-inhibiting additives for low-foam cleaning preparations. In the above formula, n is preferably a number of from 8 to 10, the preferred radical R.sup.2 is the n-butyl radical, and the preferred value for n is the number 9. The terminally blocked polyglycol ethers of this type are preferably used in such quantities that their concentration in the ready-to-use cleaning solutions is from 10 to 2500 ppm and preferably from 50 to 500 ppm. These terminally blocked adducts of ethylene oxide with relatively longchain alcohols are useful both with respect to their performance properties and above all with respect to their biological degradability.
However, in the practical application of surfactant components of this kind, it has been found that they develop their optimum activity at temperatures of about 50.degree. C. and higher, whereas at lower temperatures improvements in their foaming behavior appear desirable, particularly when they are used in cleaning processes which promote foaming from the mechanics of the process. Copending application Ser. No. 077,257, filed July 24, 1987 to Schmid et al. relates to improvements in this class of biologically degradable low-foam surfactants. This earlier application relates to low foam or rather foam-inhibiting surfactant mixtures based of water-soluble and/or water-emulsifiable polyalkylene glycol ethers of relatively long-chain alcohols, wherein these surfactant mixtures contain components I, II and, if desired, III identified below in the following quantitative ratios (the quantities in % by weight each being based on the total weight of the mixture of components I to III):
(I) from 20 to 80% by weight polyethylene glycol ethers corresponding to general formula I EQU R.sub.1 --O--(CH.sub.2 CH.sub.2 O).sub.n --R.sub.2 (I) PA0 in which PA0 (II) from 10 to 40% by weight alkyl polyalkylene glycol mixed ethers corresponding to general formula II ##STR2## in which R.sub.3 is a linear or branched C.sub.8 -C.sub.18 alkyl radical, PA0 (III) from 0 to 40% by weight alkyl (poly)propylene glycol ethers corresponding to general formula III ##STR3## in which R.sub.4 is a linear or branched C.sub.16 -C.sub.22 alkyl or alkenyl radical and PA0 compounds of general formula I: 50 to 80% by weight PA0 compounds of general formula II: 10 to 30% by weight PA0 compounds of general formula III: 0 to 20% by weight. PA0 (a) from 20 to 80% by weight polyethylene glycol ethers corresponding to general formula IV EQU R.sub.5 --O--(CH.sub.2 CH.sub.2 O).sub.p --R.sub.6 (IV) PA0 in which PA0 (b) from 10 to 40% by weight alkyl polyalkylene glycol mixed ethers corresponding to general formula V ##STR5## in which R.sub.7 is a linear or branched C.sub.8 -C.sub.18 alkyl radical, PA0 (c) from 0 to 40% by weight alkyl (poly)propylene glycol ethers corresponding to general formula VI ##STR6## in which R.sub.8 is a linear or branched C.sub.16 -C.sub.22 alkyl or alkenyl radical and PA0 IV: from 50 to 80% by weight PA0 V: from 10 to 30% by weight PA0 VI: from 0 to 20% by weight.
The parts by weight of components I to III preferably lies within the following quantitative ranges:
For further details, reference is made to the disclosure of the above-mentioned U.S. Pat. No. 4,548,729 and copending application Ser. No. 077,257, of which the disclosures are specifically incorporated by reference herein.
In the meantime, it has been found that surfactants or surfactant mixtures of the type described in the above patent and pending application can be in need of improvement due to the following problems.
At low temperatures such as may prevail for example in practical application in winter, the surfactants can separate from their aqueous solutions. Aqueous solutions of low-foam surfactant components, particularly those described in U.S. Pat. No. 4,548,729, show corresponding separation, for example at temperatures below 5.degree. C. Also, improved solubilities are desirable in another special field of application, i.e., in preferably strongly acidic cleaning formulations. Low-foam surfactants of the described type show inadequate solubility, for example, in formulations containing phosphoric acid, particularly at high phosphoric acid contents.